Protocol for micropropagation of quercus spp

Abstract

Oaks are important broad-leaved hardwood species of forest ecosystems, valuable from economical and ecological point of view. The preferred means of oak propagation is from seeds, what favours broadening of genetic diversity of these species. However, the possibilities of generative reproduction are limited by long life span necessary for achievement of physiological maturity, by irregular occurrence of mast years, by low crop and quality of seeds and difficulties in acorn storage. Seeds of Quercus species show different degrees of recalcitrance and can be stored only for a short period because of their sensitivity to desiccation. In addition, the conventional method of vegetative propagation of mature trees by cuttings is associated with difficulties in rooting. The problems in oak propagation from juvenile or mature material could be solved by the use of in vitro techniques. In vitro propagation from dormant buds collected from mature trees is important especially for the commercial forestry, for clonal propagation of selected genotypes with valuable wood quality, resistant or tolerant to diseases and to conditions with increased pollution. In vitro propagation from juvenile material enables production of large number of vital plants of diverse genotypes necessary for the maintenance of genetic diversity in forest ecosystems. Immature and mature zygotic embryos are potentially suitable sources of explants for oak micropropagation. The cultures of excised embryos are practical and effective techniques of in vitro propagation. Using them the premature abortion of zygotic embryos, derived from open or controlled pollination, can be overcome and also their dormancy can be reduced or broken. In this chapter, the micropropagation protocol for Quercus spp. using explants from juvenile material (embryos and seedlings), as well as from selected mature trees is described.